The Obama administration has warned Beijing about keeping its agents away from prominent expatriates living in the US, The New York Times reports. China reportedly wants to repatriate some of them to face corruption charges at home.

US officials revealed that there are Chinese law enforcement agents covertly operating in America, who are part of a global operation titled “Operation Fox Hunt.” These agents are trying to track down and repatriate Chinese citizens, allegedly to recover illegally obtained funds, the NYT reported.

China does not have an extradition treaty with the US, nor does it have one with Australia, Canada or New Zealand.

Reportedly, China was asked to put a stop to its agents’ activities in recent weeks, with American officials citing concerns around “strong-arm” tactics used by the agents, who are from the Ministry of Public Security, China’s main law enforcement agency.

The operation is said to be a part of Chinese President Xi Jinping’s battle against corruption. Since 2014, over 930 suspects have been returned home, according to the Ministry of Public Security. Chinese media have reported that teams of agents have been sent out around the globe.

The agents are likely entering the US on tourist or trade visas, the American officials said.

China asserts it respects local laws overseas and its agents do not make arrests on foreign soil.

Chinese state news media in April published Interpol alerts for 100 people that Beijing wants to apprehend, describing the people on the list as China’s most-wanted fugitives worldwide.

American experts cited by the NYT doubted the Chinese government’s claims, however, saying pointing that none of the people on the list are top-ranked officials.

Still, one of the men being tracked down by Chinese agents is wealthy businessman Ling Wancheng, who has connections to the top of the Chinese hierarchy. Last year Wancheng fled to the US, and now lives in a luxurious villa outside Sacramento. If the businessman applies for political asylum in the US, this could be one of the biggest defections from China since the 1949 Revolution.

“The United States is not a safe haven for fugitives from any nation,” said Marc Raimondi, a spokesman for the Justice Department, adding that if Beijing needs to track down fugitives, it must provide evidence to the US Department of Justice.

Neither China’s Ministry of Public Security, nor the Ministry of Foreign Affairs, immediately responded to the report.

Ahead of Xi Jinping’s upcoming visit to Washington, diplomatic tensions between China and the US have been on the rise. The issues of spying and the unexpected currency devaluation have taken center stage.

The US, however, is also known for sending its agents covertly into many countries across the world, at times with orders to kidnap or kill. Following the September 11, 2001 attacks on the US, teams of CIA operatives were sent abroad to kidnap Al Qaeda suspects.